Engine testing apparatus



July 4, 1950 M. c. PATTERSON Erm. 2,513,816

ENGINE TESTING APPARATUS Filed Aug. 24. 1945 2 Sheets-Sheet 1 WZZE/ Pzzw/ Il duff /7 Trai/Fys July 4, 1950 M. c. FucrTERsoN ErAL 2,513,816

ENGINE TESTING APPARATUS Filed Aug. 24, x14945 I 2 Sheets-Sheet 2 `I3, water pump I4, `and exhaust fan I5.

Patented July 4, 1950 ENGINE TESTING APPARATUS Matthew C. Patterson, Grosse Pointe Park, and Joseph A. Baker, Roseville, Mich., assignors to Chrysler Corporation, Highland Park, Mich., a

corporation of Delaware Application August 24, 1945, Serial No. 612,478

13 Claims.

This invention relates to a method and apparatus for testing engines. More specifically it relates to testing an engine under various load conditions with the various steps of the test carried out automatically` Provision is made for failure of the engine `to pass its test to prevent the testing of another engine unless an appropriate person in charge of the test is notied.

An object of the present invention is to provide an improved method and apparatus for test ing an engine under various conditions of load. The apparatus may include appropriate devices for carrying out parts of the test automatically and for automatically regulating times of the various parts of the test.

set the engine for making possible the testing of a second engine.

Other objects will appear from the disclosure.

in the drawings: I

Fig. l constitutes a diagrammatic showing of an engine, the novel apparatus of the present invention for testing the same, and Various associated parts;

Fig. 2 is a detail view, partly in section of a key-controlled switch constituting a part of the present invention; and

Fig. 3 is a view showing atimer for operating various switches.

The reference characters I0, II, and` I2 designate motors driving, respectively, oil pump The vmotors IU, I I, and I2 are c-onnected in parallel with one another and to a 440 volt, 60 cycle, threephase power line. A feed line I5 leads from the oil pump I3 through a valve I1 to an engine I8. A drain line I9 leads from the engine I8 through a valve back to the pump I3. A branch line 2l leads from the feed line IB through a valve 22 to a hydraulic cylinder 23. A branch line 24 leads through a valve 25 to the drain line I9. A piston 26 is slida'bly mounted in the hydraulic cylinder 23. A rod'21 is connected at one end to the piston and is slidably received at the ,other end in a sleeve 28 fixed to one end of a grod 29. The other end of the rod 29 is connected to an arm 30 fixed to a throttle valve 3l pivotally positioned in an intake manifold 32 for the enfgine I 8. A spring 33 connected at one end to a xed portion of the engine I8 and at the other end to the free end of arm 30 tends to hold the throttle valve 3| in the closed or idle position, as shown. `A feed line 34 leads from the water pump I4 to the engine I8, and a drain line 35 leads' from the engine to the water pump.

A motor 35 is adapted to be connected through a switch 31 with the three-phase power line. The switch 31 is adapted to be closed by the action of current flowing in a control represented diagrammatically .as 9, coil 38 forming part of I'a circuit 39, which also includes a manually operated switch 49 and a switch 4I adapted to be closed through'a speed responsive element, not shown, operating from the exhaust fan I5. Also rincluded in the circuit 39 is a secondary coil l42 of a transformer, which also has a. primary coil t3 in one of three lines 44 leading from` the switch 31 to the three-phase power line. The

`motor 35 drives a generator 45, which is adapted to start the engine I8 and to supply the ignition current thereto. The ignition current is supplied 'through la, circuit 46, which includes the ground 41, a manually operated switch 48, a switch 49 closable in response to a predetermined pressure in the Water feed line 34, a switch 53 closable in response to a predetermined pressure in the oil feed line I6, and a ground 5I.

The engine I8 isdrivingly connected with an inductor generator 52, which is adapted to'be connected through a switch 53 and three lines 54 with the three-phase power line. The switch 53 is .adapted to be closed by a control 54a diagrammatically represented as a coil. The coil 54a is in a line 55 extending from a junction point l56 throughl switches 51, 58, and 59 to a junction point 90. Between the junction points 56 and 60 is a line in which are positioned a, manually controlled switch 6I and the secondary coil S2 of a transformer, the primary coil 63 of which is connected across two of the lines 54. The 440 volts supplied to the primary coil 63 by the threephase power line are reduced to volts in the secondary coil 62. The switches 51 and 59 are vdesignated respectively with the additional charymeans of a time relay twenty minutes after the starting point and ve minutes after the starting point. An arrow is applied to the switch 451,110 show a movement toward an open position of the switch, and this means that the switch is lowed by the letter M `and also :an arrow in@ dicating movement toward the closed position of the switch or the open position thereof. Each supplementary reference accompanied by the letter M indicates that the switch is controlled by the time relay and is adapted tobe closed or opened a certain number of minutes after the starting point. The direction of the arrow indicates whether the switch is to be closed or opened. The switch 58 carries the additional designation of 1200 R. P'. M. and an arrow pointing to closed position of the switch. This means that the switch is closed when the engine reaches the speed of 1200 R. P. M.

Lines 321 and 64' lead respectively from juncnon points en and es to junction points ss and 66. A line 6'! leads from the junction point 65 through a switch 68 adapted, as indicated, tovbe Y closed iteen minutes after the starting point and through a solenoid 69 'to' the junction point 66, the solenoid controlling the drain valve 20 and the oil drain line I9. Line 'II leads from junction 66 to junction 13. Continuation of line 63 leads from junction 65' to ljunction 12. A line 74 leads from the junction point 'I2 through a solenoid 'l5 controlling the oil feed valve I1 in the feed line I6 and through a switch I6 to the junction point 7f3. As indicated', the switch 'I6 is adapted to be opened seventeen minutes after the starting point. A line 'I'I leads from the junction point. 'I2 through a solenoid'l', and

switches 'i9 and 80 to the junction point 73. The

Asolenoid 83 adapted to operate by a current in the line 54 representing fullloadj upon the engine I8 to open a switchI 84.y The switches 82 and 84 are connected in a line 85 leading from the junction point 86 on the line 63a through the switches 82, and 84, a switch 81, the solenoid 88 controlling the valve 22, and a switch'89 closable ve minutes after the starting point, as indicated, back to a junction point 39a on the line 64. Connected in parallel with theswitoh 82 is a switch 90 closable seventeen minutes after the starting point.

And connected in parallel with the circuit portion including switches 8T and 89 are a switch 9| closable eighteen and` one-half minutes after the starting point and a solenoid 92 controlling the switch 81. The solenoid 92 is ,adapted to move the switch 8l from the position .show-n in Fig. 2, in. which it contacts the line` 85 tov a position in rwhich it closes a circuit 93 which includes a rejection lamp 94 and an electric power source such as. a battery 95.

' The apparatus and equipment just described are adapted to beused for testing the engine or motor 4 I8. The procedure for operating in conducting' the test is 'as follows.

First, the motors I0, II, and I2 are started in order to start the oil pump I3, the water pump I4, and the exhaust fan I5. These may be part of a central system that supplies oil, water, and air to a plurality of engines being tested, but only one engine I8 to be tested is shown. Then the manual switch is closed, and when the exhaust fan -I5 has reached a suicient speed, the speed responsive switch 4! closes causing current to ow in the coil 33, which closes the switch 3l connecting the motor 39 through the lines 44 to the three-phase power supply. The motor 36 starts the generator 45. Thereafter the engine I8 is placed on the test stand, connectionsl are made for ignition, starting, gas, oil supply, oil drain, water and exhaust, and the engine is coupled to the inductor generator 52. Then the test may be made for engine timing by suitable means, not shown. rIhereupon the manual switch 48 is closed for engine ignition. Suitable means, not shown, may be provided for interconnecting the manual switch 48 with the manual switch El for closing these two switches simultaneously. Closing of the switch 6I causes current to flow through the solenoid 'I5 thereby opening the valve I1 in the oil feed line i6 permitting oil to pass through the engine and'out through the drain line I9 through open valve 20 in the drain line. When the oil and water pressures in the feed lines I6 andl 3d have reached predetermined values, the switches 50 yandV 49 close causing current to be supplied from the generator to the ignition system of the engine, and the engine is thereby started. Thereupon the throttle valve 3l is connected to the hydraulic piston ZilbyV attachment ofthe rod! 29to thearrn 30. An appropriate stop against which theV throttl-evalve 3|: is to be returned to idleV position by the spring 33 is adjusted for a desired idling speed of the engine, for example, 500 R, P. M. Thereupon a time relay device, one appropriate forml of which is hereinafter described, may be set in motion. Such procedure may involve, for example, starting an appropriate motor. The' setting in motion or the starting of the time relay apparatus marks the starting point previously referred to. This starting time is the zero time for all time-responsive switches.

Five minutes after the'starting point the switch 89 closes as indicated, and current hows through the solenoid 88, thereby causing the valve 22 to open. This action causes oil to be fed from the feed line I6 through the branch line 2I into the hydraulic cylinder 23. The valve 25 is normally closed at this point since the switches 79 and 80 are closed and consequently, current flows through the solenoid 18 to hold the valve 25 closed. Thus the piston 26,15 moved in a downward direction as viewed in Fig. 1 and acts through the rods 2l and 29 to increase the opening of the throttle valve 3l. In the meantime, the switch 59 will -alsohave closed, i. e., after the elapse of rive minutes from thev starting point. When the lincrease in the openingof the throttle valve 3| is suiiicient to cause the engine speed to reach 1200 R. P. the switch 58 closes. This switch may be appropriately controlled by electronic means, not show-n, operating from the ignition system of the engine. Closing of the switches 58 and 59 causescurrent to owin the. control coil 54a, thereby closing the switch 53 connecting the inductor generator 521 through the lines 5'4 to the three-phase lpower line. Thus a load is applied asis-,821e

by the inductor generator to the engine, and whenl one-half ratedload yis reached as represented yby a certaincurrent flowing from the inductor generator through the lines 54 `of the three-phase power line, the solenoid 8| opens the switch 82. Opening of the switch 82 interrupts iiow of current through the solenoid 88 thereby closing the valve 22 and-holding the piston 26 and the throttle valve 3| against movement. The arrival at one-half load may be appropriately in- Idicated on a control board by means, not shown,

connected for example, with the switch 82 so that a check may be made as to proper performance during the one-half load period. The switch 'I9 acts to prevent racing of the engine in the event that the inductor generator 52 is not connected with the lines 54 or that there is a failure of power in the three-phase power line. In the aforesaid events the engine will go to an overspeed of 1400 R. P. M. at which point the switch 'I9 will open causing interruption of current to the solenoid i8 and thereby opening the valve 25 exhausting oil from the cylinder 23 to the line 24 to the drain line i9. This permits the throttle valve 3| to return to idle position under the action of the spring 33. The switch 'I9 may be under control of electronic means,fnot shown, operated by the ignition system of the engine.

Fifteen minutes after the starting point or in other words, ten minutes after the period leading to one-half load was started, the switch 88 closes as indicated thereby causing current to flow through the solenoid 89 and closing the oil drain valve 20. Now the levelof the oil in the engine I8 rises. Two minutes thereafter or seventeen minutes after the starting point the switch 16 opens, as indicated, causing the current to stop flowing through the solenoid and causing the valve 'I'I vto close. This stopsthe supplying of oil to the engine by the external oil pump I3 and the engine now operates upon its own oil pump.

At the saine time, i. e., seventeen minutes after the starting point, the switch 98 connected in parallel with the now open switch 82, closes and current again flows through the solenoid 88 f l causing the valve 22 to open and oil to be admitted from the feed l1ne I8 to the branch line 2| to the cylinder 23. Thus the piston 28 moves downward in the cylinder as shown and acts through the rods 21 and 29 to increase the opening of the throttle valve 3 I. Speed of the engine is increased, and the inductor generator 52 feeds more current through the lines 54 into the threephase power lines. When the current in the lines 54 corresponding to full rated load of the engine is reached, the solenoid 83 causes the switch 84 to open. This action interrupts flow of current through the solenoid 88 causing the valve 22 to close. The piston 28 is held against movement in the cylinder 23 and similarly the opening of the throttle valve 3| is fixed. The arrival of the engine at full load may appropriately be indicated through a light on the yto control board, not indicated, operated for example, by opening of the switch 84. At this time the engine may be checked for proper performance during the full load period.

At twenty minutes after the starting point or in other words, three minutes after the period for full load was started, the switch 88 is opened as indicated, causing interruption of current ow in the solenoid 'I8 and opening of the valve 25. This permits the oil to drain from the cylinder 23 through the line 24 to the oil drain line I9 andthe throttle valve to return to idle position period, the switch 51 opens interrupting ow ofY current through the control coil 54a. This causes the switch 53 to open and the load of thethreephase power line to be removed from the inductor.

generator 52. Thus the load is removed from the engine I8.

In the event that the enginefails to pull its full loadduring the three-minute period seventeen to twenty minutes after the starting point the switch 8K1y Will remain closed. At the half-way point in this three-minute period, i. e., eighteen andv one-half minutes after the starting point, the `switch 9| closes, as indicated, causing `the solenoid 92 to shift the switch 8l to the right from the position indicated, causing the line to be broken and the circuit 93 containing the rejection lamp 94 to be closed. Lighting of the rejection lamp 94 indicates that the engine `has failed to pull full load; the switch 8l can be returned to the position shown only by means of a key supposedly used only by an authorized person such as an inspector or a foreman, to whose attention the failure of the engine must come, as will later be described with reference to Fig. 2. Otherwise the rejection lamp 98 will stay lit and the circuit containing the solenoid 88 controlling opening of the valve 22 for feeding oil to the cylinder 28 for increasing the opening of the throttle valve 3| may not be closed. Thus unless the failure of the engine to pull full load is called to the attention of an authorized person having the key permitting release of the switch 81 to the position shown, another engine cannot be put through the above described test.

When the test of the engine is over, the engine is appropriately disconnected from various parts of the testing apparatus and is removed from the stand.

Fig. 2 shows an embodiment of an apparatus b`y which the switch 8l may be controlled. The switch 8l has a stem 98 about which the solenoid 92 is coiled. An inclined projection 9i xed to the stem 98 is engaged as shown by an inclined face of a dog 98. A spring 99 acting between the dog 98 and a piece |88 urges the dog into the position of Fig. 2. The dog 98 is slidably mounted between a plate Iill and a block |82. The switch 8l and its stem 92 are urged to the left and maintained in the position of Fig. 2 by a coil spring |83 acting between a collar |84 fixed to the end of the stem 98, the plate IUI, and a part |85. When current passes through the solenoid 92, because the switches 84 and 9| are closed, the switch 81 and its stem 95 are urged to the right from the position of Fig.' 2 to a position in which the switch no longer closes the line 85, but closes the circuit 98 of the rejection lamp 94. `The stern 98 may move to the right, for the inclined faces on the projection 9i and the dog 98 cause the dog 98 to be moved upwardly against the spring 99. The projection Si thus moves past the dog 98 to the right, and the dog returns to the stem 98. Now there is contact between the right side of the dog 98 and the left side of the projection 91, preventing the stem 98 and switch 8'! from returning to the left and thus keeping the circuit 93 closed and the rejection light 94. Also the line 85 is kept open and thus current cannot flow through the solenoid 88 for opening the valve 22 for opening the throttle valvel 3| by oil control. Thus another engine cannotbe tested. An authorized person may insert a key |08 in an opening in the block |92.

Thekey. engages a. recess lill Ain-thedogaJv and. by.: a. clockwise movement.. will raise the dogy 98. out or theV way ofthe projection Si? toV permit the-returned. the.. stem .95 .and ther switch 81. to. the left .under theaction of .the spring H13. This causestherejection lamp 9.1i to be extinguished and .the line` 85 to. beclosed..

Fig. 3 shows a timer |58 for the various-.timeresponsive.switchesv .The timercomprisesa dial landrotating, hand or army mounted-on. apivot.. tlhandsuitably Adrivenby. a time mech. anisnn notshown.. The. arm |||I` isy connected. through. its pivotill with a suitable source ofl electric power. suchas a battery H2. The battery MZ isconnectedthrough a line 4| |3v witha lunction-.point .|I4, from .which leads aline H5.` A. solenoid .|.|6,.operating the switch 5.5 is connected to. the..line. |15 at a junction point thereon. A. solenoidv H8, operating., the switch 89, is connectedwith the line through a junction point ila therein.y The twosolenoids |16 and. ll are connected at. a` junction. point |20 `with a line |2 l which is.. connected with a.V conductor |22. in the. timerilli..v Frorna junction point |23 in the linel tlieadsa line. |24 to ajunction pointV |2510 which is. connected a. solenoid.. |26, which vopcrates the. switch 6.8. Aline |2`| leads from .the solenoid |26 toa conductor |28. in the timer IBB... Fron1.,the. junction.A point |25 leads the line |29. tdajunction point |35, to which is connected a solenoid |,3|op.erating the switch. 1.6. A solenoid 32.. which operates the switch 90 is connected to the junction point |30. The. solenoids |3| .and IZLare connectedY to a junction point |33 fromV which leads a line |34 to a conductor |35 inthe timer IBB.;` In the line |I5 is connected. a sole.- noid |36 operating the switch B|, and the line Lliconnects the. solenoid |35 with a conductor. |31, inthe timer |98. From the junction point H4 leads a line |38 to a junction point |39, to which are. connected in parallel solenoids |45 and L4M., which operate, respectively, switch Sii and switch 51. The solenoids 11|) and MI are con.- neciedat a junction point |42 from which leads a line |113y tol a conductor |44 in the timer |58. In Fig 3 switches 59, 58, 89.. 99, and 9| are shown toibe open, and when current is suppliedvto their respective solenoids these switches will be `closed. Switches. 51.'. l5, andv 8.0 are shown to be closed, and. when current is. supplied to their respective solenoids, they will be opened. At the start of the.specincation, the timer arm H0 is at, the zero point as shown in Fig. 3. When ve minutes fromthestarting, point of the test have. elapsed, the arm- HQ will contact the conductor |22, the end of which carries a designation 5. `Upon Contact ofy the arm H5 with the conductorv |22, a circuit is closed from the battery ||2 through the arm ||.|l, thev solenoids H6. and H38, and the conductors Hand M3. The energization of the solenoids M5 and H8 causesthe switches 59 and 819 to close. As time. elapses after the five-minute point, thearmv til-staysin contact with the con* ductor |22, and the switches. 59 and lle-continue shut. When l5 minuteshaveelapsed from the start of the test, the arm HD; will contact the conductor |28, closingr a circuit through the solenoid |25.. which closes the switch 68. Thel arm HG, stays inA contact with the conductor after the leminutepoint to maintain theswitch 58 closed. When 17 minutes have elapsed from the starting point of the test, the arm ILD, reaches the conductor |35thereby closing a circuit .through the solenoids, |34Y and |32.;vl causing them, respectively,

'the test of the engine as previously described in toopen the switch 16 and to close. the switch 9U. Thereafter the arm |.|0 stays in contact with the conductor |35,4 causingthe switch i6 to be kept open and the. switch to be kept closed. When 181/2; minutes have elapsed from the starting pointfoi the test .the arm |||l reaches the conduetor |31 causinga circuit. to be formed through the solenoidV |36, which. closesv the switch. 5|. Continuance of the contact of the arm with the conductor I3? keeps the switch 9| closed. When20. minutes have elapsed from the start oi the test,the. arm contacts the conductor |44, causing cur-rent to flow through the solenoids |411 and 14|, which now open the switches. 51 and 85. The conductors |22, |28, |35., |31,` and |44 may extend. beyond the 20-minute point so far as is convenient for maintaining the time-responsive switches in their relative positonsat theZO-minute point.

InfsoI-ne cases the engine may be so constructed ormodied. byauxiliary. devices such as special jets for the carburetor that it will pull a greater load .than thatv representedy by the current in the. one line 54 that will open the. switch Sil-.by means of the' solenoid 83. In this eventthe throttle valve 3|y may beopened by hand further than the piston 25 would open it, the sliding connection of the rod 2-in the sleeve 28 attached to the rod. 2Q-permitting movement of therod 2S. independent oi the rod 21.

Although. various. engine speeds. and times have been indicated for operating switches described in regard tothe present invention, it is to be understood .that the. values supplied are merely illustrative and are not to. be considered as limit-'- ing the inventionI beyond the scope and ,spirit of thc.- appended claims.

Weclaim:

l., AnA apparatus for testing an engine having a. throttle valve, comprising; hydraulic means; for adjusting the. throttle. valvev to obtain settings of. the throttle valve for .no load, half load,.and fullfload., electric means for controlling the hydra-ulic means sowas. to` establish periods oi time for running theengine at the various loads, the electric .means including a switch adapted to be openedl to prevent adjustment of the hydraulic means for preventing adjustment of. the throttle Valve bysaidhydraulic means and bengclosable only with a; key',l and. means. responsive to failure of; the enginel to pullifull load. during the. full load period, for openingl the switch.

2..'Iestingfv apparatusior an.. engine provided with positionable. means for admitting fuel having positions corresponding to predetermined values. of powerV output desiredv of the engine: comprising electrical operating means; vadapted for connection. with the positionable fuel, admit.- til-igmeans,L an electrical generatoradapted to` be connected to. loadr and to. be'driven by the engine, time responsive control elements for causing. the electrical operating means to.- ohange the position of the fuel-'admitting' means. at certain times, and means responsive to powery output of the generatorforinterrupting-1the changing of the fuel admitting-,means position by the electrical operating meansupon attainment-trof a predetermined power. output fromsaid electrical generator.

BrApparatus. for utilizing av power generator and-a load forfreceiving power therefromto test a power,- plant which 'includes a. prime, mover drivingly connectable to said generator and a regulatable: tuel.` admitting means; comprising means? for regulating the.. fuelr admitting means; time-responsive elements fory causing;I the' regu-,-

lating means at certain times to advance regulation of the fuel admitting means for an increased fuel rate from no load and part load and to retard regulation of the fuel admitting means for a decreased fuel rate from full load to no load7 means responsive to engine speed for connecting the power generator to the load so as to load the prime mover, and means responsive to power output of the generator to the load for causing the regulating means to fix the regulation of the fuel admitting means for part load of the prime mover and for full load of the prime mover.

4. Apparatus for testing an engine having a throttle valve, comprising hydraulic means for controlling the opening of the throttle valve including a cylinder for pressure fluid and a piston slidably mounted in the cylinder and connected to the throttle valve, electrical means associated with the hydraulic means for causing the same to control the throttle valve as aforesaid, means for supplying electrical current to the electrical means and interrupting the supplying thereof including switches openable and closable at certain times and under certain loads for acting through the electrical means and the hydraulic means to regulate the throttle valve for running the engine for predetermined times at no load, half load, and iull load, and further including a switch openable in response to failure of the engine to pull full load during the time period for full load to interrupt the flow of current to the electrical device and closable only with a key.

5. An apparatus for testing an engine, comprising means for admitting fuel to the engine, control means responsive to time and to the operation of the engine under various conditions such as no load, half load, and full load for acting through the fuel-admitting means to operate the engine for certain times from no load to full load and back to no load, means responsive to failure of the engine to operate at full load during the time period for full load to set the control means against the aforesaid action on the fuel-admitting means for preventing the testing of another engine, and key-controlled means for resetting the control means to provide for the aforesaid action by the control means on the fuel-admitting means.

6. Apparatus for utilizing an electrical power load to test a prime mover provided with a throttle control having a normal range of motion between idling and full power positions: comprising automatic means adapted for operative connection with the throttle control to be effective for automatically advancing the throttle for at least a part of its normal range of motion, electrical energy generating means connectable to the electrical power load for loading said generating means, said electrical energy generating means being adapted for drive receiving connection with the prime mover to form therewith a power plant, the output power of which being consumed by the electrical power load, means responsive to predetermined power output of the power plant occasioned by the throttle advance effected by said automatic means, for interrupting further throttle advance, and means for reducing the power output of the power plant from said predetermined value and for removing said electrical power load including electrical means effective to cause retarding motion of the throttle control.

7. Apparatus for testing an engine comprising means for admitting fuel to the engine, electrical means for regulating the fuel-admitting means, an inductor generator adapted to be driven by the engine, time-responsive switches for causing the electrical means to adjust the fuel-admitting means from no-load to part load to full load and back to no load at certain times, means responsive to engine speed for connecting the inductor generator to a power line for loading the engine, means responsive to failure of the engine to operate at full load during the proper time therefor to set the electrical means against adjusting the fuel-admitting in order to prevent the testing of another engine, and y key-controlled means for resetting the aforesaid means. v

8. Apparatus for testing an engine comprising means for admitting fuel to the engine, electrical means for regulating the fuel-admitting means, an inductor. generator adapted to be driven by the engine, time-responsive switches for causing the electrical means at Acertain times to increase the rate of the fuel-admitting means from no load and part load and to decrease the rate from full load to no load, means responsive toengine speed for connecting the inductor generator to a power line so as to load the engine, and switches responsive to current output by the inductor generator to the power line to cause the electrical means to fix the fuel-admitting means for part load of the engine and for full load of the engine.

9. Apparatus for testing a prime mover having regulatable means for admitting fuel to the prime mover, comprising means for regulating the fueladmitting means, an inductor generator adapted to be driven by the prime mover at a frequency proportional thereto, a power lineenergized at a constant electrical frequency, means responsive to a predetermined rotative frequency of the prime mover for connecting the inductor generator to the power line whereby load can be applied to the prime mover, time-responsive elements forcausing the regulating means at certain times to increase the rate of the fuel admitting means from no load and part load and to decrease the rate from full load to no load, and elements responsive to current output by the inductor generator to the power line to cause the regulating means to fix the fuel admitting means for part load of the prime mover and for full load of the prime mover.

10. Apparatus for testing an engine, comprising means for admitting fuel to the engine, electrical means for controlling the fuel-admitting means, an inductor generator adapted t0 be driven by the engine, means for connecting the inductor generator to a power line to load the engine, time-responsive switches connected with the electrical means for adjusting the fuel-admitting means for predetermined time periods at no load, part load, and full load, a speed-responsive switch connected with the means connecting the inductor generator and the power line for causing the power line and the inductor generator to be connected to one another above a predetermined engine speed, and means connecting the speed-responsive switch and one 0f the timeresponsive switches for preventing connection of the inductor generator and the power line for a predetermined no-load period in spite of operation of the engine above the predetermined speed.

11. The apparatus specified in claim 10 and further comprising a switch openable in response to failure of the engine to pull full load during a full load time period for disabling the electrical means in its control of the fuel-admitting means so as to prevent the testing of another, means preventing closing of the last mentioned switch, and key-controlled means for releasing the last fuel-supplying means,

Y 11 mentioned means to provide )for return of the switch torclosedposition.

1'2. Apparatus for testing an-fengne comprising means for admitting fuel to the engine, electrical meansfor regulating the fuel-admitting means,

and inductor generator adapted to be driven by y the engine, time-responsive switches for causing the electrical means at certain times to increase-thefrate of the fuel-admitting means for no `load and part loadand to decrease the rate fromfull load to vno load, means responsive to engine speed for connecting the inductor generator to a power line so as to rload the engine, switches responsive to current output by the Inductor generator to thefpower line to cause the electrical means to x thefuel-admitting means for half load of Athe engine and for full load of the engine, means responsive to failure of the engine to operate at full load during the proper time therefor to setY the electrical means against adjusting the fuel-admitting inorder to prevent the vtesting-of another engine, and key-controlled means lfor resetting the aforesaid means.

13. Apparatus for testing an engine having a `comprising hydraulic meansfor controlling the opening of the throttle valve including a cylinder and a piston slidably mountedtherein and connected with the throttle valve, an electric device adapted by receiving currentto cause the hydraulic means to increase the opening of the-throttle valve and by failing to receive current to cause the hydraulic means toix the opening ofthe throttle valve, means for supplying current to the electrical device comprising Va source of electrical power and a circuit connecting the source of electrical power andthe electrical device Aand including a rst Aswitch closable after a-rstpredetermined time from a starting point to supply current to the electrical device for causing the latter to Amake the hydraulic means increase'the opening of the throttle valve from idle position, a second switch openable upon the assumption of half load by the engine for interrupting flow ofA current tothe elecl2 trical ldevice to 'cause'thehydraulic means to'flx the opening of the throttle valve for half load on the engine, -a third switch closable after a second predetermined time from the starting point greater than the rst predetermined time and acting in parallel with the -second switch now open to supply lcurrent to the electrical device for causing the hydraulic means to increase the opening of the throttle valve from the position forhalf load on'the engine, Aa fourth switch openable upon the assumption of full load by the engine to interrupt the flow lof current to the electrical device for causingthe hydraulic means to x the opening of the throttle valve for full load on the engine, a fifth switch closable after a third predetermined time from the starting point greater than lthe second predetermined time,vand a `sixth switch openable in response to closing of the 'fth switch and failure of the fourth switch to yopen for interrupting flow of current to the electrical device and closable 011157 by means of a key a seventh switch openable after a fourth predetermined time from the starting point greater than the third predetermined time for causing the hydraulic means'to return the throttle valve to idle position, and means for operating the rst,.third, fth, and seventh switches as aforesaid at the various times specified therefor after'the starting point.

MATTI-[EW C?. PATTERSON. JOSEPHYA. BAKER.

REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number "Name v Date l1,508,353 Scott Sept. 9, 1924 y1,635,980 Highfield etal July 12, 1927 y2,175,681 Brunner Oct. 10, 1939 2,362,682 Watson Nov. 14, 1944 2,394,131 Wrathall et al Feb. 5, 1946 MNA Certificate of Correction Patent No. 2,513,816 July 4, 1950 MATTHEW C. PATTERSON ET AL.

It is hereby certied'that error appears in the printed specication of the above numbered patent requiring correction as follows:

Column 3, line 44, for oened read opened; column 8, line 52, after the Word period strike out the comme; column l1, line 6, for and read an;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oflce.

Signed and sealed this 10th day of October, A. D. 1950.

[sun] THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

